Transmission And Evolution Of Optical Solitons In A Negative Refraction Material

The permittivity and permeability are the physical attributes to describe the basic electromagnetic properties. They are all positive in natural materials. But in theory, materials possess negative permittivity and permeability do exist, one of which is negative-index material(NIM).This medium has many characteristics which general material doesn't have, such as the negative refraction index, evanescent wave amplification, reversed Doppler effect, perfect lens. For those reasons, NIM quickly became a international research focus. In recent years, the research about NIM is not only in microwave band, but also in terahertz, infrared, even in optic band, and the properties of nonlinearity are studied, too. As the important field of nonlinear optics, solitons could propagate in a long distance without the change of shape. Therefore solitons have a broad use in high-rates fiber-optic communication systems.This dissertation firstly introduced the basic principle of NIM. By comparing the traditional material, showed the unique phenomena in it, and summarized the recent researches internal and abroad. Then based on the theory of solitons in general material, a new Schr?dinger equation which describes the solitons'propagation in NIM is found. The high-order nonlinear effects are quite different from the situation in normal material for the existence of dispersion permittivity and permeability. We used a numerical method called Split-Step Fourier Method. In order to ensure the accuracy and reducing computation time, different iterations are used for different parameters. The results accorded with the theoretical analysis.Then, the roles of the fifth-order nonlinear effect, controllable self-steeping, high-order dispersions, and nonlinear dispersions are analyzed in the anomalous-GVD regime and normal-GVD regime, separately. The negative fifth-order nonlinear effect compresses the pulse width and cycle of bright solitons, and will case the splitting of high-order solitons. For dark solitons, it mainly affects the gray soliton's amplitude. In NIM, the SS coefficient can be negative, so the offset direction of solitons is in opposite of the normal material's. With the interaction of third-order dispersion, the self-steeping could disappear in NIM. As a unique property, the nonlinear dispersion is similar in the form with the linear dispersion, but it will split the soliton's spectrum and make the propagation instability when it exists alone. It mainly changes the amplitude of solitons in actual use. At last we investigated the soliton interactions in NIM and discussed the reasons of attraction or rejection between two solitons. We proposed a new model, using an input pulse with the different amplitude, different phase and zero-SS under the circumstance of third-dispersion, to ensure the two solitons propagate without interaction.